Filter media can be used to remove contamination in a variety of applications. Depending on the application, the filter media may be designed to have different performance characteristics. In general, filter media can be formed of a web of fibers. The fiber web provides a porous structure that permits fluid (e.g., a liquid or a gas) to flow through the filter media. Contaminant particles contained within the fluid may be trapped on the fibrous web. Filter media characteristics, such as fiber diameter and basis weight, affect filter performance including filter efficiency and resistance to fluid flow through the filter.
Fiber webs can be formed by different processes. In a meltblowing process, a fiber web may be formed by extruding a polymeric material through a die and then attenuating the resulting filaments with a heated, high-velocity air stream. This process may generate fine fibers that can be collected onto a moving collector belt where they intertwine with each other to form a fiber web. There are several parameters during the extrusion process that can affect the structural and performance characteristics of the resulting fiber webs. Improvements in the extrusion process may lead to fiber webs having improved structural and performance characteristics, such as reduced fiber diameters, increased surface area, and/or reduced basis weight. Such improvements would find use in a number of different fields where fiber webs can be used, such as in filtration applications.